green spot algae

[jesse270]

Hey guys I'm still pretty new the the whole planted tank I have a problem with gsa on my plant leaves and this is causing the ends to curl over and leaf will eventually fall off. It is happening on about every leafy plant especially on my Hygrophila guyanensis I don't get much gsa on glass but some is on the driftwood.

My tank is about 5 months old now, Few fish. 450ltr planted tank with co2 and moderate lighting. Good water flow, about 22mg co2 a ltr at a pH of 7.1. Nitrates at 15ppm and phosphates kept around 2ppm.

I also follow the seachem dosing chart. And I also have root tabs. I also do a 30% water change weekly. The leaves that have the gsa seem to be a darker colour. I'm not sure if this is a deficiency or overdoes of ferts. Can a potassium deficiency cause this?

[Tech Support AN]

Re: green spot algae

Thanks for the post and we are sorry to hear about your plants. I may need some additional information in order to troubleshoot further.

Can you please be more specific about the "gas" on the leaves? Maybe provide a picture?
Which products are you using in the tank?
Do you use RO water or tap water?


Potassium deficiency usually shows as tiny pin holes in the leaves. Are you seeing this with any of your plants?

Sorry for the questions, but if you can provide as much information as possible, we would be happy to help you figure out what is happening.

[jesse270]

Re: green spot algae

The GSA is in most of the older growth. I'm using all the seachem line. I'm using tap water that has a hardness of 8-9. not really any pinholes in the leaves.But I had the issue even before I even used root tabs (only put them in 2 weeks ago). I just decreased lighting down to 6 hours a day this past few days. It was never more than 10 hours a day before. I post pics when I get the chance. I follow your dosing chart exactly except for phosphates and nitrates. Can excess flourish build up cause GSA?

[jesse270]

Re: green spot algae

my leaves

[Tech Support AN]

Re: green spot algae

LOL! I'm so sorry, as I did not realize you said "gsa". My apologies for the confusion. :)

Flourish can certainly cause algae when over used, as it does contain organics. We recommend dosing the Flourish only once or twice a week.

It sounds as if you have a little bit of an imbalance with your nutrients. Is this a heavily planted tank? If not, it could be that you are dosing too many nutrients and the plants are not able to utilize them quickly enough, therefore, the algae begin to consume them. Are you using tap water? If so, have you checked the phosphate and nitrate levels in the tap? Do you dose the Flourish Nitrogen and Flourish Phosphorous or do you rely on fish waste to provide those nutrients? When dealing with GSA, it can take a little time before you can achieve the right balance of nutrients. I would start with focusing on the phosphates and nitrates, as these are primary contributors to algae issues. If you are using tap water that contains phosphates and nitrates, you could switch to using RO water, which would give you a clean slate to start with and you could add the nutrients as needed. That might be a more expensive option, but it is an option.

[jesse270]

Re: green spot algae

hi ill say its heavily planted with a small amount of fish. I dose the recommended dose of flourish twice a week. Tap water phosphate and nitrate levels are so low as is not reading on the test kits so I add extra using Flourish Nitrogen and Flourish Phosphorous. Keeping my phosphates at 2ppm and nitrates 10- 15ppm. I've tried bringing my phosphates too 0 and it seem to get a lot worse. I'm thinking I either need to add more flourish or less. Its hard to see the GSA in the pics but I have also recently trimmed the tank. But its still lingering around on older growth. Here's a pic anyway.

[Tech Support AN]

Re: green spot algae

Thanks for the picture! Your tank looks fantastic!

I would not recommend bringing your phosphates to zero, as this is usually a trigger for algae. Typically, you want to keep your nitrates and phosphates at about a 5:1 N:P ratio and you never want either element to be zero. This is the proper ratio that plants are able to utilize the nutrients and out compete the algae. Once this balance is out of whack, than the algae will begin to utilize the nutrients and starve out the plants.